Poor and Good visibilities in warm sectors

Figure 1 – Courtesy of the Met Office

Since moving down to the southwest some fifteen years ago now, I have noticed it’s often the case that in warm sectors (fig 1) although Cornwall and west Devon are plagued by extensive sea fog and low stratus, away from high ground, and in the lee of Dartmoor or Exmoor further east surface visibilities are often remarkably good, such is the case this morning (fig 2).